Noxious Weeds Wyoming Weed & Pest Designated Weed List Field bindweed Leafy spurge Perennial sowthistle Quackgrass Hoary cress (whitetop) Perennial pepperweed (Giant Whitetop) Ox-eye daisy Skeletonleaf bursage Russian knapweed Yellow toadflax Dalmation toadflax Scotch thistle Musk thistle Common burdock Dyers woad Houndstongue Spotted knapweed Plumless thistle Diffuse knapweed Canada thistle Purple loosestrife Common St. Johnwort Saltcedar Common tansy Russian olive Black henbane Sublette County Declared Weed List Scentless chamomile Western water hemlock Field scabious Austrian fieldcress Cheatgrass Hoary alyssum